Abstract
Abstract There is a high demand for cultural weed management strategies targeting Palmer amaranth ( Amaranthus palmeri S. Watson) in furrow-irrigated rice ( Oryza sativa L.) production due to overreliance on herbicides and the lack of a continual flood to prevent weed emergence. Amaranthus palmeri has been shown to reduce corn ( Zea mays L.), cotton ( Gossypium hirsutum L.), and soybean [ Glycine max (L.) Merr.] yields when it interferes with the crop. However, minimal research has been conducted to assess the ability of this weed species to impact rice grain yield. The manipulation of rice seeding rate to enhance rice canopy formation and favor the crop over the weed has not been fully explored. Hence, research was conducted to (1) evaluate the effect of rice density on A. palmeri emergence, rice canopy cover, and relative yield; and (2) determine the impact of A. palmeri density and aboveground biomass on rice grain yield. A natural population of A. palmeri was allowed to emerge at varying densities throughout the growing season within furrow-irrigated rice. Amaranthus palmeri plants caused 12% to 87% yield loss at densities ranging from 1 to 20 plants m −2 , and yield loss was 45% to 80% for plants weighing 200 to 800 g m −2 . When furrow-irrigated rice was sown at various densities, crop canopy cover increased as rice plant density increased. Most A. palmeri emergence occurred within the first 4 wk after rice emergence, before canopy formation could have an effect. Amaranthus palmeri emergence beyond 5 wk after rice emergence decreased as rice plant density and canopy cover increased. These results indicate that A. palmeri has the potential to cause severe yield loss and that residual herbicides will be vital for A. palmeri management in a furrow-irrigated rice system, due to the continual emergence of weeds up to crop canopy formation.
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Claims 6
Claim · model-written summary
Amaranthus palmeri plants caused 12% to 87% rice yield loss at densities of 1 to 20 plants per m2.
- Taxon
- rice
Oryza sativat0 - Treatment
- densities ranging from 1 to 20 plants m −2e1
- Interactor
- Amaranthus palmeri
Amaranthus palmerie1weed - Outcome
- yield losse1
- Direction
- losse1
- Value
- 12% to 87%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“furrow-irrigated rice system”
e1“Amaranthus palmeri plants caused 12% to 87% yield loss at densities ranging from 1 to 20 plants m −2”
Claim · model-written summary
Rice yield loss was 45% to 80% for A. palmeri plants weighing 200 to 800 g per m2.
- Taxon
- riceOryza sativat0
- Treatment
- plants weighing 200 to 800 g m −2e1
- Interactor
- A. palmeriAmaranthus palmerie2weed
- Outcome
- yield losse1
- Direction
- losse1
- Value
- 45% to 80%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“furrow-irrigated rice system”
e1“yield loss was 45% to 80% for plants weighing 200 to 800 g m −2”
e2“the impact of A. palmeri density and aboveground biomass on rice grain yield”
Claim · model-written summary
Crop canopy cover increased as rice plant density increased.
- Taxon
- riceOryza sativae1
- Treatment
- rice plant densitye1
- Outcome
- crop canopy covere1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“crop canopy cover increased as rice plant density increased”
Claim · model-written summary
Most A. palmeri emergence occurred within the first 4 weeks after rice emergence, before canopy formation could have an effect.
- Taxon
- riceOryza sativae1
- Interactor
- A. palmeriAmaranthus palmerie1weed
- Outcome
- A. palmeri emergencee1
- Value
- 4 wke1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Most A. palmeri emergence occurred within the first 4 wk after rice emergence, before canopy formation could have an effect”
Claim · model-written summary
Amaranthus palmeri emergence beyond 5 weeks after rice emergence decreased as rice plant density and canopy cover increased.
- Taxon
- riceOryza sativae1
- Treatment
- rice plant densitye1
- Interactor
- Amaranthus palmeriAmaranthus palmerie1weed
- Outcome
- Amaranthus palmeri emergencee1
- Direction
- decreasede1
- Qualifier
- beyond 5 wk after rice emergencee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Amaranthus palmeri emergence beyond 5 wk after rice emergence decreased as rice plant density and canopy cover increased”
Claim · model-written summary
Residual herbicides will be vital for A. palmeri management in furrow-irrigated rice because of continual emergence up to canopy formation.
- Taxon
- riceOryza sativae1
- Interactor
- A. palmeriAmaranthus palmerie1weed
- Outcome
- A. palmeri managemente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“residual herbicides will be vital for A. palmeri management in a furrow-irrigated rice system”
The same questions in other papers
density · growth · Oryza sativa (rice)Positive and negative results
72 papers in the same direction as this paper · 23 in the opposite direction
- no effect
- no effect
- negative
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See all 96 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.